Propeller fan blade retaining construction



8, 1952 w. E. MORRISON PROPELLER FAN BLADE RETAINING CONSTRUCTION Filed NOV. 2]., 1946 2 FIG-3.- 33 22 23 36 [NVENTOR' M m R W m A M MY m W Patented Jan. 8, 1952 UNITED-STATES PATENT osrlcs I PROPELLER FAN BLADE RETAINING CONSTRUCTION William E. Morrison, Torrington, Conn assignor to The Torrington Manufacturing 00., Torri-ngton, Conn.,a corporation of Connecticut Application November 21, 1946, Serial No. 711,273

7 Claims. I r 1 This invention relates to improvements in propeller fan blade retaining construction, and more particularly to a novel and improved construction of the elements of; propellers of spiderless type, being those in which the blades are directly carried by a center disc or plate, connected as through a hub, to the shaft. The invention lsparticularly, but by no means exclusively, applicable to heavy dutyfans of larger diameters.

It has heretofore been known to construct propellers, particularly propeller type fans, by avoidance of separate blade mounting arms, spiders or the like, as by attachment of the blades directly to a single. rigid armless mounthig ele'; ment. Structures for this purp e. a hou h utilized in limited number, offer certain objectlcns, among which are a relatively high production cost, and therequirement in some cases at least, of an odd :and expensive formation of hub or center disc. The present invention accordingly has as a principal objective, the attainmentcf a-propeller of a type in which the blades are directly carried by a center disc of a sturdy planar form and of .low cost construction.

Yet another object .of the invention is attained in an improved construction of the root portions of the several propeller blades, such that each of the blades may be economically and r gidl attached to a planar center element such as a plate, and correctly, uniformly and permanently pitched with respect to such plate. The foregoing and numerous other objects will more clearly appear from the following detailed description of a presently preferred form or embodiment of the invention, particularly when considered in connection with the accompanying drawing, in which: Fig. 1 is a rear view of a fan, constructed in accordance with the present improvement;

F 2 is a somewhat enlarged partial section through the. hub, center disc and. one of the gades, particularly as taken along line lbs-:2 of,

g. l; rig. 31s a fragmentary sectional elevation, the sectional portions of which are taken along line .3-3-o.1' Fig.1; r

Fig. 4 is a fragmentary rear view of .a slightly modified form pi fan, and

Fig. 5 is a side view of a shipping package comprised of the major parts .of the fanas same might appear in the term of .a unit sold as an article of manufacture, tor assembling the fan. Referring now by characters of reference to the drawin here'has been selected as a pre- 2' ferred structure to illustrate the points of present novelty, a four blade propeller type fan in which the several blades are each indicated generally at -l 0, a center plate or disc by which the blades jllare carried, being designated general y at H. The disc II is secured to a hub l2 for shaft mounting the assembly .on a suitable power shaft or the like (not shown) a The hub 12 is of a generally .cylindricalform including a shaft bore l3, together. with set screws [-4 and 1.5 each occupying a suitable tapped aperture. An originally thin reduced end of .hub 12 extends through a central opening l6 of the center plate ll, and be ond the open n I6, i flared outwardly as by spinning, swaging or by impact means such as a highspeed hammer, so that in coaction with a shoulder H, the resulting flaredportion 20 serves, with the shoulder, firmly to grip the margins of the metal adjacent aperture 16 to h ld the pla e nd hub in permanent assembly.

The center disc or plate H is preferably provided with a pluralityof openings or. bolt holes one of, which appears in Fig. 2 and is indicated at 2|. By reference to Fig. 1 it will be seen that tour such holes are provided about an inner circle relatively close to the hub 12, while near the periphery of the center disc is provided a similar circle of bolt ,holes (not shown), holes serve to receive assembly bolts 22 in the outer circle, and 23 in th inner c rcl i a e nuts 24., with lock washers or their equivalents, coact with the bolts in assembly. I

. In the form shown by .Fig. .1, the center .disc is provided with a series of notches 25. In this construction 'the notches .open inwardly from the periphery of the disc ll and each is shown as substantially coincident with the radius of the fan, and hence with the radius of the disc. These notched portions coact with the blade root portions and bolts in locating and angularly positioning the fan blades, as will hereinafter more fullyapp a Proceeding now to a description of the con struction. of blades and blade root portions,'th displacement portion of each blade I'D i's pre'fer ably a pitched sheet metal element, the particular configuration and conformity of which is chosen for best displacement characteristicsthe displacement portion of each blade being indicated at 26, It may be assumed that the fan as shown in Fig. l is I'Qtated in the counterclock wise direction, the displacement portions of the blades serving to move the air toward the leftas Viewed .inFig. 2. The direction in whicjh'the air These rows of v the inner row in the center plate or disc.

is moved will be regarded as the forward direction and the left face of the fan as viewed in Fig. 2 will be regarded as the front or forward face.

The displacement or main portion of each blade is at an acute angle to the faces of the disc H, and each blade has an inner portion 3| which is also at an oblique angle to the faces of the disc. The said inner portion 3| is preferably partly within the corresponding notch 25 in the disc and it has opposite edges which project forwardly and rearwardly beyond the respective faces of the discs as clearly shown in the cross sectional portion of Fig. 3. The inner portion 3| of each blade has furcations or tabs, preferably three in number and respectively designated as 30, 32 and 36, the general arrangement of the said furca- -mined direction which may be counterclockwise,

as viewed in Fig. 1. It will be seen that the trail- 'ing' lateral tab on each blade overlaps the leading lateral tab on the next following blade. The holes in said trailing and leading tabs are in register with each other and also in register with tions or tabs being best illustrated in Fig. 5.

haveportions 34, 34 with faces which are perpendicular to the axis of rotation and which re spectively engage the front and rear, faces of the disc II. The portions 34, 34 of the tabs and 32 are provided with bolt holes 35, 35 for the reception .of the before-mentioned bolts 22, 22. v

The intermediate furcation or tab 36 of, each blade extends inwardly and is twisted to consti tute a flat or planar securement portion, this beingprovided with a bolt hole 35 similar to those in the tab portions 34,34. 7

It should be observedthat although the center disc H is of appreciable thickness, it is most desirably of planar form, and the securement tabs are also all preferablyof planar construction, and arranged in mutual parallelism or in substantially coplanar relation, so that in assem bly, the tabs will lie flat against the lateral sur faces of the disc, assumed for present description 5 J to be planar.

a by the provision of the, several notches 25. As-

sembly of the blades to the center disc after complete formation thereof, may be readily and easily effected by insertion of each blade JD, with its .median root portion traversing one of the notches 25. When thus positioned, the secure-- ment tabs 30 and 35 of each blade engage the rear side of the center disc and the other tab 32 of the same blade engages the opposite side of the disc, with each of the bolt holes 35 in register with corresponding holes in the center disc. The. holes in the lateral tabs 30 and 32 are in-register. with a pairof widely angularly spaced bolt holes near the periphery of the disc, as will appear from Figs. 1 and 3, and the hole 35 in the center tab 36 is in register with one of the bolt holes of It is a preferencein assembling the blades to the disc, to minimize the number of bolts and boltv openings, and better to tie together the blade roots to each other and to the disc, by overlap ping the lateral tabs of adjacent discs, whereby larly adjacent blades, and a registering opening in the corresponding hole in the disc for the reception of the corresponding bolt.

A somewhat modified form of fan embodying the present principles is shown by-Fig. 4} this fan being adapted for rotation in the .clockwise direction. The principal difference in construction lies in the fact that the blade lllA is provided with'a notch 25A, the center disc 1 IA being either devoid of peripheral notches as shown, or optionally notched to a lesser extent than as shown by Fig. l. In'the modification the three securement tabs 30A, 32A and 36A are pro-' vided with holes quite similar to those shown at 35, bolts 22A engaging an outer circle'in element A, and bolts 23A occupying an inner circle in locations corresponding to b'o1ts23. The present fan is particularly adapted for larger types and sizes of heavy duty propellers; although by no means exclusivelyintendedfor such restricted fields of usage. In these fields it is of course of considerable advantage to provide a fan of knock-down type. This objective is promoted byformation of blade roots and the blades themselves in such manner that they may be. readily stacked or nested in a compact package as shown by Fig. 5, a part of which package consists of a companion center disc and hub assembly Ii -12$ It, is now evident th'atsubstan tialeconomies in shipping and storage spacewill resultffrom this feature.

It will'be seen that the present structurejalso lends itself admirably to the provision of relatively few standardized center disc or plate members each of which may be adapted to fan blades of a variety of lengths and shapes, but with sii'nilarly formed root portions, thusenabling assem bly on the job of fans of diiferent sizes 'with certain parts standardized through a moderate range of fan diameters. In distinction from certain older less satisfactory types of spiderless propellers, the presentarrangement presents a rugged, permanent assem bly in which the center assembly occupies but a minimum of space axially of the propeller, and may utilize standard lengths of hub. It avoids the difficulty of imparting and maintaining QX'. act twist tospider arms of the more conventional structures, and tests have indicated even under operation at speeds far in excess of rated rates of rotation, there results virtuallyno distortion or change in pitch of any of the blades, and no deviation from original 'balanca'fin spite of "the simplification of structure. When sold, "as a knock-down package unit, as per Fig. '5 forex ample, 'the fan may be initially assembled for finishing and balancing, then disassembled for packaging.

Obviously, in 'case'of noneces'sity ror-or' ad seam vantages "in a knock-down package, the major elements may be assembled by rivets, or by welding as desired, in lieu rof the bolted construction described.

Thus the present ss'ervcs fully to attain each and -all of the several objectives :above :set forth and others implied from the description. Although the examples herein are disclosed by detailed reference to their various elements and features, this detail of description [is to be understood solely in an informative rather than. any limiting sense, many structural variants being possible within the scope of the claims hereunto appended.

I claim as my invention:

.1. The combinationin a fan, of aicircular central disc provided with flat front and rear faces and adapted to be mounted for rotation in a predetermined direction about a central axis perpendicular to the said faces, the said disc having a plurality of circularly spaced holes extending therethrough near its periphery and also hav ing a. plurality of additional holes extending therethroug-h, a plurality of radially extending air moving blades each having a main portion at an Oblique angle to the faces of the disc, each blade having two inwardly extending tabs widely spaced circularly and having inner faces perpendicular to the axis of rotation and respectively engaging the front and rear faces f the disc which tabs are positioned with the trailing tab on each lblade overlapping the leading eaten the next following blade and which tabs have holes therein so located that the hole in the trailing tab on each blade is in register with a corresponding hole in the disc and is also in register with the hole in the leading tab on the next following blade and each blade also having an additional inwardly extending intermediate tab engaging one face of the disc and having a hole in register with one of the said additional holes in the disc, a plurality of fastening devices each extending through the hole in the trailing tab on a corresponding blade and through the corresponding hole in the disc and through the hole in the leading tab on the next following blade, and a plurality of additional fastening devices each extending through the hole in the central tab on the corresponding blade and through the corresponding additional hole in the disc.

2. The combination in a fan, of a circular central disc provided with flat front and rear faces and adapted to be mounted for rotation in a predetermined direction about a central axis perpendicular to the said faces, the said disc having a plurality of circularly spaced notches therein extending inwardly from its periphery and the said disc also having holes extending therea through near its periphery and circularly spaced from the said notches, a plurality of radially extending air moving blades each having a main portion at an oblique angle to the faces of the disc and each having aninner portion at an oblique angle to the faces of the disc and extending through a corresponding notch each of which inner portions hasopposite edges which project forwardly and rearwardlyv beyond the said disc faces and each of the said blades also having two Widely spaced tabs extending directly from the said inner blade portion at the said opposite outer edges thereof which tabs throughout their radial dimensions are offset toward the disc from the respective edges .of the said inner portion and have inner faces perpendicular to the axis of rotation and respectively engaging the front and rear faces of the-disc, the trailing tab on each blade overlapping the leading tab on the: next following blade and the said tabs'having holes therein so located that the hole in the trailing tab on each blade is in register with a corresponding hole in the disc and isalso in register with the hole in the leading tab on the next following bladefiand a plurality of fastening devices each extending through the hole in the trailing tab one, corresponding blade and through the corresponding hole in the; disc and through the hole in the leading tab on the next. following blade.- i

3. In a propeller type fan, a relatively heavy planarcen-ter plate, a ,hub for shaft-mounting. the-fan, assembled to the center region of the plate, a plurality of blades directly assembled to the plate, each blade having its root portion formed to result in three blade securement tabs, namely, a center tab and apair of lateral or out-' side tabs, certain of said tabs of eachjblade engaging opposite faces of the center disc, means: for securing the tabs to the faces of the disc, the center tabs of each blade being secured inwardly of the disc periphery and relatively close to the hub, and the lateral or outside tabs of each blade being secured near the periphery of the disc.

4. The combination and arrangement of elements as recited by claim 3, but further characterized in that certain of the tabs of each blade are mounted in straddling relation-to the periphcry of the center disc, the =-tabs being provided with apertures and the center .disc' provided with registering apertures, and assembly bolts extending through the registering apertures of the center disc and the said tabs.

5. A heavy duty propeller type fan of spiderless constructidn consisting of a hub provided with a shaft-receiving bore, a center disc of rel atively heavy planar plate construction and substantially circular outline, a plurality of blades each directly carried by and pitched relatively to the center disc, each blade having a root portion of trifurcate construction, the three furcations of which are angularly spaced in location, about the center disc, the furcations formed and serving as tabs for securement of the blade to the disc, the several furcations being of angulate section and each being apertured at its extremity, the furcations of each blade including a center securement tab, and a pair of widely angularly spaced, lateral securement tabs, the center disc being provided with an inner row of bolt openings, bolts extended through each of the center tabs of the several blades and through one of the openings of said inner row, the center disc further provided with an outer row of bolt apertures, bolts extended therethrough, the outer tabs being formed and perforated to register with said openings, and to receive bolts in the last said openings, the center disc being notched inwardly from its periphery, and along radii coincident with the longitudinal median lines of the several blades, with a portion of the root of each blade extended into one of the said notches, the notches and engagingblade root portions, serving angularly to locate and to key the several blades in fixed angular relation to the center disc.

6. In a propeller fan construction of spiderless type, a center disc, a plurality of blades, each blade including a root portion formed to provide three blade securement tabs directly engaging surface portions of said disc, and assembled thereto; one tab of each blade secured to the disc substantially in the region of a longitudinal blade median produced inwardly along the disc;

and other tabs of the same blade engaging. the disc in regions widely angularly spaced from said first tab with the trailing tab of each blade over-' lapping the leading tab of the next following blade, and fastening means forsecurement of the tabs to the center disc, certain of said-fase tening means being common to the said overlapping tabs of adjacent blades.

7. The combination in a fan, of a circular central disc provided with flat front and rear faces and adapted to be mounted for rotation in a predetermined direction about a central axis perpendicular to the saidfaces, the said disc having circularly spaced holes extending therethrough near its periphery, a plurality of radially extending air moving blades each having a main portion at an oblique angle to the faces of the disc and each having an inner portion at an oblique angle to the faces of the disc each of which inner portions has opposite edges which project forwardly and rearwardly beyond the said disc faces and each of the said blades also having two widely spaced tabs extending directly 'from the said inner blade portion at the said opposite outer edges thereof which tabs throughout their radial dimensions are offset toward the disc from the respective edges of the said inner portion and have inner faces perpendicular to the axis of rotation and respectively engaging the front and rear faces of thedisc, the trailing tab on each blade overlapping" the leading tab on the next following blade andthe said tabs having: holes therein so located that thepholein the trailing tab on each blade is in'register with a corresponding hole in the disc and is also in register with the hole in the leading tab on the next following blade, and a plurality of fastening devices each extending through the hole in the trailing tab on a corresponding blade and through the corresponding hole in the disc and through the hole in the leading tab on the next following blade.

wmLmM E. MORRISON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 530,356 Great Britain Dec. 10,- 1940 

